Sampling Schemes for Studying Growth of Children

Efficiency of linked cross-sectional scheme has been compared with pure longitudinal schemes for generalised estimation of norm relaxing the condition of constancy of variances. The relevant theory of estimation has been developed and the expression for the optimum estimators alongwith their variances have been derived. The percentage gain in efficiency has been calculated. It has been observed that for higher values of Q, percentage gain in efficiency of proposed scheme over cross-sectional is very high.     

Paraquat depresses the activity of angiotensin converting enzyme expressed by human umbilical vein endothelial cells in culture

The activity of angiotensin converting enzyme (ACE) in cell lysate of cultured human umbilical vein endothelial cells (HUVEC) after a 24-hour incubation with 10(-3) and 10(-4)M of paraquat (PQ) was decreased. However, LDH released into the culture medium of HUVEC during the 24-hour incubation with PQ was not increased. Many investigators show that the change in serum ACE activity reflects the impairment of vascular endothelial cells. We showed in this report that ACE was decreased even at an early stage of endothelial injury induced by PQ, when LDH release is not yet increased.     

A new method of isolation and a new form of transketolase from baker's yeast]

A new procedure for the isolation of homogeneous transketolase from baker's yeast based on the use of enzyme-specific antibodies immobilized on a insoluble matrix has been developed. The enzyme yield is 90% of its total content in the original yeast extract. The eluate from the immunocolumn was found to contain a previously unknown form of transketolase which represents an enzyme-RNA complex.     

A consensus sequence of plant hemoglobins

From the study of plant hemoglobin protein and gene sequences, a consensus sequence was constructed and analysed by computer methods; analysis comprised the amino acid composition, hydropathy profile, and match degree with other plant and non-plant hemoglobin sequences. Resulting consensus sequence shows the main features of hemoglobin genes and proteins in plants.     

Laetoli toes andAustralopithecus afarensis

The probable misfit between feet, particularly toes II–V, of 3.0-million-year-oldAustralopithecus afarensis from Hadar, Ethiopia, and the 3.5-million-year-old hominid footprints at Site G, Laetoli, Tanzania, casts doubt thatA. Afarensis made the Laetoli trails. We suggest that another species ofAustralopithecus or an anonymous genus of the Hominidae, with remarkably humanoid feet, walked at Laetoli. It would be imprudent to declare thatHomo was present at Laetoli 3.5 million years ago (my) because there is no evidence of brain expansion, advanced tool manufacture, or other non-locomotor hallmarks of the human condition at Site G.     

Macrophage catabolism of lipid A is regulated by endotoxin stimulation

Lipopolysaccharide (LPS) is a Gram-negative bacterial glycolipid that is believed to cause, by virtue of its stimulatory actions on macrophages and other eukaryotic cells, the life-threatening symptoms associated with Gram-negative infections. Macrophages both respond to and catabolically deactivate LPS. The lipid A moiety of LPS is responsible for the stimulatory actions of LPS on macrophages. We have previously developed methods employing a radiolabeled bioactive lipid A precursor, 4'-32P-lipid IVA, to study the interaction of this class of lipids with animal cells (Hampton, R. Y., Golenbock, D. T., and Raetz, C. R. H. (1988). J. Biol. Chem. 263, 14802-14807). In the current work, we have examined the uptake and catabolism of 4'-32P-lipid IVA by the RAW 264.7 cell line in serum-containing medium at physiological temperatures and have studied the effect of LPS stimulation on the ability of these cells to catabolize lipid IVA. RAW 264.7 macrophage-like cells avidly take up 4'-32P-lipid IVA under cell culture conditions at nanomolar concentrations. Uptake of lipid IVA was accompanied by lysosomal dephosphorylation of a fraction of the lipid to yield 4'-monophosphoryl lipid IVA. Chemically generated 4'-monophosphoryl lipid IVA was found to be substantially less bioactive than lipid IVA in the RAW cell, indicating that this catabolic dephosphorylation results in detoxification. In uptake experiments of 3-4 h duration, all metabolism of lipid IVA is blocked by ligands of the macrophage scavenger receptor. In longer experiments (24 h), both scavenger receptor-dependent and -independent uptake are responsible for the lysosomal catabolism of lipid IVA. Preincubation of RAW 264.7 cells with LPS caused dose-dependent inhibition of lipid IVA dephosphorylation. Sufficient LPS stimulation resulted in essentially complete inhibition of lipid IVA catabolism in both short- and long-term uptake experiments. This effect occurred at physiologically relevant concentrations of LPS (IC50 less than 1 ng/ml), and our data indicate that LPS-induced blockade of lipid IVA catabolism was due to the resultant physiological stimulation of the cells, and not inhibition of dephosphorylation by competition for uptake or enzymatic sites or by simple sequestration of labeled lipid IVA by LPS aggregates. We suggest that in the macrophage, LPS can modulate its own catabolism by virtue of its pharmacological properties. This effect of LPS could play a role in LPS pathophysiology as well as in macrophage biology.     

Carbonmonoxy dopamine beta-hydroxylase. Structural characterization by Fourier transform infrared, fluorescence, and x-ray absorption spectroscopy

The carbon monoxide complex of ascorbate-reduced dopamine beta-hydroxylase has been prepared and characterized by Fourier transform infrared, fluorescence, and x-ray absorption spectroscopies. CO has previously been shown to be a competitive inhibitor with respect to O2, and binds to only one of the two copper atoms/active site (Blackburn, N. J., Pettingill, T. M., Seagraves, K. S., and Shigeta, R. T. (1990) J. Biol. Chem. 265, 15383-15386). Thus, it acts as an excellent probe of the O2-binding site. A single C-O infrared absorption band is observed at 2089 cm-1, shifting by 46 cm-1 to lower energy on substitution with either 13C16O or 12C18O. The 13C isotope shift is reversed to the position expected for 12CO upon vacuum flushing with 12CO gas, indicating that formation of the CO adduct is a fully reversible process. Binding of the substrate tyramine does not eliminate the infrared peak but causes a 3-cm-1 shift to lower energy. On the other hand, binding of a bifunctional inhibitor which cross-links the substrate and O2-binding site does eliminate the CO peak. These data, in conjunction with the competitive nature of CO binding with respect to O2, identify the CO-binding site as the O2-binding site, and place it in close proximity to the substrate-binding site. CO-dopamine beta-hydroxylase exhibits no luminescence in the visible region, suggesting a structure different from carbonmonoxy hemocyanin, and in all probability mononuclear. Analysis of extended x-ray absorption spectroscopy data is most consistent with an average coordination per Cu of 2-3 histidines, 0.5 CO, and 0.5 S atoms as ligands, and absorption edge comparisons indicates pseudo-4 coordination as the most likely geometry at each Cu(I) center. The results can be interpreted by a model involving inequivalent 4-coordination at each Cu(I) center in the CO adduct with CuAHis3S...CuBHis2CO-X as the coordination most consistent with all of the data.     

Mutations in a newly identified Drosophila melanogaster gene, mago nashi, disrupt germ cell formation and result in the formation of mirror-image symmetrical double abdomen embryos.

The mago nashi (mago) locus is a newly identified strict maternal effect, grandchildless-like, gene in Drosophila melanogaster. In homozygous mutant mago females reared at 17 degrees C, mago+ function is reduced, the inviable embryos lack abdominal segments and 84-98% of the embryos die. In contrast, at 25 degrees C, some mago alleles produce a novel gene product capable of inducing the formation of symmetrical double abdomen embryos. Reciprocal temperature-shift experiments indicate that the temperature-sensitive period is during oogenetic stages 7-14. Furthermore, embryos collected from mago1 homozygous females contain no apparent functional posterior determinants in the posterior pole. In viable F1 progeny from mago mutant females, regardless of genotype and temperature, polar granules are reduced or absent and germ cells fail to form (the grandchildless-like phenotype). Thus, we propose that the mago+ product is a component of the posterior determinative system, required during oogenesis, both for germ cell determination and delineation of the longitudinal axis of the embryo.     

Gelled diet for screwworm (Diptera: Calliphoridae) mass production

A rearing system based on a diet gelled with Water-Lock G-400, a synthetic superabsorbent (poly(2-propenamide-co-2-propenoic acid, sodium salt)) (WL), was compared with the standard rearing system (liquid diet suspended in acetate fibers) for the mass production of screwworms, Cochliomyia hominivorax (Coquerel). The WL rearing system yielded 2% heavier pupae, 32% higher egg to pupa survival, and required 54% less diet and 88% less labor than the standard rearing system. Other advantages of the WL system include reduced susceptibility to suboptimal environmental conditions and labor practices and characteristics conducive to centralization and mechanization of rearing procedures.